JP4936689B2 - Metal decoration sheet for deep drawing molding - Google Patents

Description

The present invention includes automobile interior and exterior, furniture, building materials, audio, personal computers, mobile phones, PDAs, cameras, video cameras and other amusement products such as pachinko / pachislot, signboards, displays, nameplates, frames, For cosmetic cases, jewelry, tableware, toys, etc., these metal products and resin parts that add a metallic appearance to the surface of the above-mentioned resin products and resin parts are replaced with metal materials and resin plating products without reducing the sense of quality. it can, can correspond to deep drawing, further saving process, low cost, to metallic decorative sheet for deep drawing product molding can be achieved, such as weight reduction at the same time.

  As a method for imparting a metallic luster to the surface of a resin molded product, particularly a molded product having a cubic curved surface or three-dimensionality, plating or painting has been performed after molding. However, these methods require environmental measures such as waste water and solvent vapor, and also have problems such as high cost.

  Here, the proposal which obtains the molding which uses the metallic decoration sheet | seat which has a metal vapor deposition film | membrane together and has a metallic luster on the surface by insert molding has been made.

  Recently, new polyester resins with significantly improved stretchability when used in films and sheets, such as polyester polymer compounds that have benzene rings and cyclohexane rings in the main chain, have been supplied recently. In the case where a film or sheet made of such a resin is applied, it is possible to cope with a molded article having a relatively small three-dimensional shape, such as a conventional automobile side molding, as well as a so-called bowl shape, cup shape, box shape, etc. It has become possible to apply to deeply drawn products.

  In the case of such a metallic decorative sheet using a new polyester film, the film itself has extremely good stretchability, whereas the metal film formed on this film is more compatible with this stretch. It was not possible to improve it.

  Here, it is widely known that indium is more malleable than aluminum, and the present inventor also uses a metallic decorative sheet having an indium metal vapor-deposited film, which is more in comparison with an aluminum metal vapor-deposited film. As a metallic decoration sheet that can be used for deep drawing, a metallic decoration as shown in Japanese Patent Application Laid-Open No. 2002-370311 (Patent Document 1) or Japanese Patent Application Laid-Open No. 2004-001243 (Patent Document 2). I have proposed a seat.

However, despite such various studies by the present inventors, it is sufficiently deep and withstands deep drawing, for example, in particular, car emblems, front grills, mirror housings, lamp reflectors, garnishes and luxury home appliances, cosmetic cases, It was not possible to obtain a metallic decorative sheet that could give a gloss with the same depth as a mirror-like plated product obtained by applying chrome plating, which is required in fields that require a high-class feeling such as jewelry. .
Japanese Patent Laid-Open No. 2002-370311 JP 2004-001243 A

The present invention improves the above-mentioned conventional problems, is compatible with films and sheets made of a recent polyester resin and improved in stretchability, and can be applied to various molded articles, and can withstand deep drawing and deep drawing. An object of the present invention is to provide a metallic decorative sheet for forming a deep-drawn molded product capable of imparting a deep luster equivalent to a mirror-like metal plated product obtained by applying chrome plating.

  In the case of a metallic decorative sheet having a highly malleable metal film such as indium, it is naturally better to use a metallic decorative sheet having a relatively thick metal film than a relatively thin metal film. It has been considered that it can cope with deep drawing with a high draw ratio.

  Here, in the case of the conventional metallic decoration sheet, the metallic decoration sheet having an indium metal film with a thickness of 5 nm to 100 nm is already known in the literature such as patent gazettes. The formation of the indium metal film is not common for general vapor deposition processors, and there is no dedicated apparatus for forming the indium metal film. For this reason, since equipment that normally uses aluminum is switched and used by performing operations such as cleaning, the cost is much higher than the cost difference between indium and aluminum, which is the reason for that. The actual situation was that not only actual practical use but also detailed examination for practical use was finally started.

  The present inventors have also studied using the knowledge of the metallic decorative sheet using the aluminum deposited film as it is in applying indium to the metallic decorative sheet, but it was initially expected as described above. Because it was difficult to deal with deep drawing, a basic review was conducted, and it was found that it was completely unexpected.

  That is, in the case of an indium vapor-deposited film, observation with an electron microscope was performed on various prepared samples, and knowledge different from conventional recognition was obtained.

  Explaining in terms of image, many fine water droplets are formed on the bathroom window glass by the water vapor in the bathroom, and the fine water droplets gradually increase over time. Just as the combined water droplets become larger, as the deposition time elapses, very fine particles of fine indium (referred to as “islands”) are formed on the film surface, and then As the “islands” made of fine indium grow and become larger, adjacent “islands” are joined together to gradually form “islands” made of larger indium.

  Here, when such an indium vapor-deposited film is stretched, the “island” itself made of indium on the film is also stretched, but rather, no indium film is formed between the “island” and the “island”. It turned out that the part of the “sea” would be expanded.

  For this reason, when the vapor deposition process has progressed and a vapor-deposited film in which large “islands” made of indium are stretched, the vapor-deposition process is not performed so much, and vapor-deposited films in which countless small “islands” are formed are stretched. Compared to the case, the “sea” portion having no “island” made of indium is present more widely. Here, in the film after stretching, if there is no “island” made of indium and the “sea” part is wide, it is recognized as “whitening” of the metal plating surface by the observer of the molded product, and as a result, the depth It was found that a gloss equivalent to that of a metal plated product cannot be obtained. The findings obtained from these studies are summarized as follows.

  (1) The indium metal layer formed on the film has a network structure with numerous fine cracks.

  (2) When a film having an indium metal film formed thereon is stretched, a crack gap is widened in the stretching direction, and as a result, a whitening phenomenon appears (it is considered to be due to light scattering).

  (3) The finer the cracks (mesh), the more uniformly the gap spreads when stretched, and the spread of each gap is suppressed, so that the whitening phenomenon is less likely to occur.

  (4) When forming a metal layer on a film by a vapor deposition method, the longer the vapor deposition treatment time, the larger the cracks (mesh) of the formed metal film, and the easier the whitening phenomenon occurs.

The metallic decorative sheet according to the present invention has been conceived based on the above-described knowledge, and in order to solve the above-mentioned problem, at least one surface is made of indium particles as described in claim 1. A metal decorative sheet for forming a deep-drawn molded product having a metal-holding film layer on which an indium thin film is formed, the particle size of metal particles made of indium formed on the surface of the metal-holding film for forming the deep-drawn molded product that There are at 100nm or 172 nm or less, and, 20 ° gloss values when stretched twice the metallic decorative sheet in a uniaxial direction is not less than 24.1% of the 20 ° gloss value before stretching It is the metal-tone decoration sheet for the deep drawing molded product characterized.

According to the metal decorative sheet for forming a deep-drawn molded product of the present invention, it can be applied to various molded products due to the above-mentioned unique configuration. At that time, it is sufficiently deep, can withstand deep drawing, and has a deep metal. Gloss equivalent to that of plated products can be imparted.

  In the present invention, the indium thin film composed of indium particles is an indium thin film formed on a film by a normal metal thin film creation means, for example, vacuum application techniques such as vacuum deposition, sputtering, ion plating, etc. It refers to those having a network structure composed of a portion where particulate indium adheres on the film and a portion where indium does not adhere or where indium hardly adheres on the film.

  In the present invention, when the metal particles made of indium formed on such a metal holding film have an irregular shape such as a jigsaw puzzle part, the particle size (average) The particle size is required to be 250 nm or less. In the case of a metallic decorative sheet having an indium thin film composed of indium particles that have become larger than 250 nm, when applied to a molded product having a deep deep drawing, a metallic luster equivalent to a deep metal plating product is obtained. Can't get. A preferred range is 200 nm or less.

  In addition, the size of such metal particles made of indium increases with the progress of the vapor deposition process, so that when the film formation is insufficient (sufficient metallic luster cannot be obtained), it becomes, for example, 75 nm or less. However, it is necessary to grow to a level that can provide a sufficient metallic luster, and specifically, the particle size of the metal particles needs to be 100 nm or more. On the other hand, if the particle size is too large, when stretched, the portion where the film between the metal particles can be seen directly becomes wider compared to the same stretch ratio when the particles are small, and as a result, good metal A plated appearance cannot be obtained. Specifically, the particle size of the metal particles needs to be 250 nm or less.

  In the present invention, the particle size (average particle size) of the metal particles made of indium formed on the surface of the metal holding film is measured and calculated as follows.

  First, a surface photograph of the indium layer formed on the surface of the metal holding film is taken with a scanning electron microscope (SEM) at a magnification ("k" times) at which each particle shape can be clearly distinguished.

  On this photograph, a square frame (with the length of one side being “L”) that contains 50 to 100 metal particles is written.

  Count the number α of metal particles entirely contained in the frame, and then, out of the particles on the frame, β represents the number of particles that are visually recognized to be 1/2 or more of the area of the particle in the frame, It is assumed that t number of particles represented by the following formula I is present in this frame, where γ is the number of particles that are recognized to be less than half of the area of the particle by visual recognition.

[Equation 1]
t = α + (3β + γ) / 4 (I)

  At this time, the area S occupied by one particle is obtained by the following formula II, and the particle diameter R of the metal particles made of indium formed on the surface of the metal holding film in the present invention is obtained by the formula III.

[Equation 2]
S = L ² / (k ² × t) (II)

[Equation 3]
R = 2 × (S / π) ^1/2 (III)

  Furthermore, in the present invention, the 20 ° gloss value when stretched twice in a uniaxial direction is 15% or more of the 20 ° gloss value of the metal tone decorating sheet before stretching, The plating-like metallic luster at the time of molding can be secured more reliably. Here, the 20 ° gloss value is a numerical value that is generally a measure of metallic luster, and in the present invention, a 20 ° gloss value measured by a Bic Gardner Micro Trigloss Glossmeter is used.

  The metallic decorative sheet of the present invention is a metallic decorative sheet having a metal holding film layer in which an indium thin film composed of indium particles is formed on at least one surface, and is formed on the surface of the metal holding film. The particle diameter of the metal particles made of indium may be 100 nm or more and 250 nm or less.

  Here, as a general configuration of the metallic decorative sheet according to the present invention, as shown in FIG. 1, a metal holding film in which an indium thin film made of indium particles is formed on one surface, indium of the metal holding film A base film layer is laminated on the thin film forming side through an adhesive layer made of an adhesive component.

  At this time, the resin film forming the metal holding film layer on the surface of which the indium thin film is formed needs to be transparent so that the indium thin film made of indium particles can be visually recognized from the outside. In this case, it may be translucent, the surface on the side not in contact with the metal layer may be subjected to various processing such as sand mat and hairline processing, or the surface on the side in contact with the metal layer As long as the adhesion with the metal layer is not lost, processing such as sand mat and hairline may be applied. Further, the film raw material may be colored by kneading the pigment, or may be printed or dyed on the film surface and / or the back surface.

  The material of the resin film forming the metal holding film layer is preferably a polyester resin or an acrylic resin. When this transparent resin film is not a polyester-based resin or an acrylic resin, there may be a case where sufficient metallic luster cannot be imparted particularly to the corners of the molded product. Alternatively, the handling process is poor, and in the laminating process for forming a metallic glossy sheet for three-dimensional molding, bonding wrinkles may occur, or metal unevenness may occur due to the elongation of the film. In some cases, a temporary support film (process film) to be peeled off is required, resulting in an increase in manufacturing cost.

  Here, as the metal holding film used in the present invention, a general resin film such as a polyester resin film can be used, but it is preferable to use a film excellent in stretchability from the gist of the present invention.

  As such a film having excellent stretchability, amorphous polyethylene terephthalate (so-called “APET”) or modified polyethylene terephthalate, that is, a polyester polymer compound having a benzene ring and a naphthalene ring in the main chain, or a benzene ring And a film made of a polyester polymer compound having a cyclohexane ring in the main chain.

  One example of such a polyester polymer compound having a benzene ring and a cyclohexane ring in the main chain is shown in chemical formula (1) (where m and n are natural numbers). When such a film composed of a polyester polymer compound having a benzene ring and a cyclohexane ring in the main chain is used, the metallic gloss feeling of the final molded product is particularly vivid, and the corner having a very small radius of curvature in the molded product. Even if it is a part, whitening, blurring, etc. do not occur.

  Transparent thermoplastic resins made of a polyester polymer compound having a benzene ring and a cyclohexane ring in the main chain are available in the form of pellets from Eastman Chemical Co., Ltd. A transparent thermoplastic resin film comprising a polyester polymer compound having a benzene ring and a cyclohexane ring in the main chain can be obtained by forming a film by a method, an extrusion method, or other known methods.

  In addition, when the metal layer holding film is composed of a polyester polymer compound having a benzene ring and a naphthalene ring as a main chain as shown in chemical formula (2) as an example, excellent metal vapor deposition and molding In addition, the metal luster is vivid, and even in corners with a very small radius of curvature in the molded product, whitening and blurring do not occur and The film thickness can be easily reduced, so that the productivity can be improved and the manufacturing cost can be reduced, and the metallic surface can be easily given a metallic luster to the complicated shape surface. become able to.

  An example of such a transparent thermoplastic resin film made of a polyester polymer compound having a benzene ring and a naphthalene ring in the main chain is Teijin DuPont Films trade name Teflex.

  The other polyester resin film that can be suitably used in the present invention is a low stretch film obtained by suppressing the stretch ratio during film formation (in this case, it may be composed of a general polyester resin). Is mentioned.

  The adhesive constituting the adhesive layer needs to be excellent in adhesiveness with the indium thin film and a base film layer described later. Such adhesives include polyurethane, polyester, polyethylene, polyamide, polyvinyl chloride, polychloroprene, carboxylated rubber, thermoplastic styrene-butadiene rubber, acrylic, styrene, and cellulose. , Alkyd, polyvinyl acetate, ethylene vinyl acetate copolymer, polyvinyl alcohol, epoxy, silicone, natural rubber, synthetic rubber, etc. However, it is necessary to select the metallic glossy sheet for three-dimensional molding in consideration of the fact that it is necessary to withstand the temperature during molding. These adhesives are applied to an indium layer or a thermoplastic resin film or to both by using a suitable solvent when used, or as an emulsion, by a known means such as a gravure coater, reverse coater, knife coater, roll coater or the like. Dry if necessary.

  The thickness of the adhesive layer is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 8 μm or less. If it is less than 1 μm, the adhesive strength may be too small, and if it is more than 20 μm, it takes time to dry, which is undesirable in terms of the process and increases the cost.

  The film constituting the base film layer in the invention (which may be a “sheet” thicker than “film” and is also included in the present invention) must be able to withstand the temperature during molding, In addition, the color such as transparency, transparency, etc. are usually not particularly required, but the color tone to the metallic luster of the surface may be affected. Considering the magnitude of the influence, polyvinyl chloride, polyolefin, The resin is appropriately selected from resins such as polystyrene, polyacrylic, polyurethane, polyamide, polycarbonate, and acrylonitrile-butadiene-styrene copolymer in consideration of heat resistance to temperature at the time of molding, economy, and the like.

  When used for insert injection molding, the base film layer is preferably made of the same resin (same color) as the resin to be injected. In addition, considering the influence of metallic luster on the color tone, it is possible to select the type of base film layer and additives (pigments, etc.) in order to positively adjust the color tone.

  The thickness of the base film layer is preferably 50 μm or more and 1000 μm or less. If it is less than 50 μm, wrinkles such as wrinkles are liable to occur during lamination with the metal holding film layer and the adhesive layer, and the sheet is liable to break during molding. On the other hand, if it exceeds 1000 μm, the moldability may decrease.

  In the metallic decorative sheet of the present invention, in addition to the metal holding film layer, the adhesive layer, and the base film layer, for example, an scratch-resistant layer made of an acrylic resin that improves scratch resistance, and an adhesive layer for laminating the layer. Etc. may be further laminated.

  The Example of the metallic decoration sheet | seat of this invention is demonstrated concretely below.

<Creation of a metal holding film having an indium thin film>
On one side of a colorless and transparent polyester film (thickness 25 μm, Teijin Teflex FT3), which is a transparent thermoplastic resin film comprising a polyester polymer compound having a benzene ring and a naphthalene ring in the main chain, a purity of 99. While maintaining the treatment time by 99% indium by vacuum vapor deposition, various metal holding films A to G having a network-like indium thin film made of indium particles were obtained.

  The indium particle size and particle spacing of these films were examined by electron micrographs. The results are shown in Table 1. Moreover, the electron micrograph which shows the state of the indium particle | grains on the metal holding films C and G is shown in FIG.2 and FIG.3.

<Creating a metallic decorative sheet>
Metal decoration sheets A to K using these metal holding films A to G were prepared. That is, a base film layer made of acrylonitrile-butadiene-styrene copolymer having a thickness of 250 μm is laminated on each metal film side of these metal holding films via a urethane adhesive layer (thickness: 5 μm) to hold the metal. A transparent surface film layer made of PMMA having a thickness of 75 μm is laminated on the film surface side (the surface opposite to the metal film side) of the film via a urethane adhesive layer (thickness 5 μm) as a scratch-resistant layer, Metallic decorative sheets A to G were obtained.

<Evaluation of metallic decoration sheets AK>
About the said metal tone decoration sheet | seat AG, the external appearance (formation external appearance) was determined visually. At this time, compared to the chrome-plated product, it was judged that a metal having an equivalent metallic luster was sufficient in appearance, “◯”, and those having a poor metallic luster were judged as insufficient in appearance, “△” Those with extremely inferior gloss were judged to be insufficient in appearance and evaluated as “x”.

  Of these metallic decorative sheets, the metal holding films C and G were stretched twice in a uniaxial direction (gripping interval: 5 cm, stretching speed: 20 cm / min). The electron micrograph which shows the state of the indium particle | grains on the metal holding films E and F after these extending | stretching was shown in FIG.4 and FIG.5.

  Furthermore, about the said metallic tone decoration sheet | seat A-E, it vacuum-forms using the test die which shows a front view in Fig.6 (a), and a side view in FIG.6 (b), By the same die as the above The appearance was visually compared with the chrome-plated product. Compare the appearance of the chrome-plated product (with particular emphasis on luster) and judge that the one with the same metallic luster is sufficient, “○”, and judge that the metallic luster is inferior. Then, “△”, a case where the metallic luster was extremely inferior was judged to be insufficient, and evaluated as “x”. These evaluation results are also shown in Table 1.

  Here, the mold shown in FIGS. 6A and 6B is used for evaluating the metallic luster at the time of stretching in the metallic decorative sheet according to Japanese Patent Application Laid-Open No. 2004-001243. Die (Fig. 6 (c) is a front view and Fig. 6 (d) is a side view test die (the same scale as the drawing of the test die in Figs. 6 (a) and 6 (b))) This enables evaluation at a deeper drawing.

  According to Table 1, the metallic decorative sheet according to the present invention is sufficiently deep, can withstand deep drawing, and can impart a deep luster equivalent to a mirror-like metal plated product obtained by applying chrome plating. I understand.

  The metallic decorative sheet of the present invention can be applied to the field where a resin molding requiring a metallic luster is required, but particularly in the field where a metallic luster having a high-class feeling such as automobiles, luxury home appliances, cosmetic cases and jewelry is required. It can be suitably used.

It is sectional drawing which shows the general structure of the metallic decoration sheet | seat which concerns on this invention as a model. It is an electron micrograph of the metal holding film C whose average particle diameter of the indium particle | grains of the indium vapor deposition film formed on the surface is 125 nm. It is an electron micrograph of the metal holding film G whose indium particles of the indium vapor deposition film formed on the surface have an average particle diameter of 310 nm. It is an electron micrograph when the metal holding film of FIG. 2 is stretched twice in a uniaxial direction. It is an electron micrograph when the metal holding film of FIG. 4 is stretched twice in a uniaxial direction. It is a figure which shows the metal mold | die for vacuum forming used at the time of the moldability evaluation of a metal tone decoration sheet in an Example. (A) It is a front view of the metal mold | die used in the Example. (B) It is a side view of the metal mold | die used in the Example. (C) It is a front view of the metal mold | die for evaluation used conventionally. (D) It is a side view of the metal mold | die used conventionally.

Claims (2)

A metal sheet for decorating a deep drawing molded article having a metal holding film layer on which an indium thin film composed of indium particles is formed on at least one surface, formed on the surface of the metal holding film for molding the deep drawn article The 20 ° gloss value when the particle size of the metal particles made of indium is 100 nm or more and 172 nm or less and the metal decorative sheet is stretched twice in the uniaxial direction is the 20 ° gloss value before stretching. A metallic decorative sheet for forming a deep-drawn molded product, characterized by being 24.1 % or more.   It has the said metal holding | maintenance film layer, an adhesive layer, and a base film layer in this order, The metal-tone decoration sheet for deep drawing molded object shaping | molding of Claim 1 characterized by the above-mentioned.